Average and Heterogeneous Associations between Secondhand Smoking and Tooth Loss

Area of Science:

• Public Health
• Epidemiology
• Dental Research

Background:

• Secondhand smoke (SHS) exposure is a widespread public health issue.
• Existing research on SHS and tooth loss lacks population-level data and subgroup analysis.
• Understanding the full impact of SHS on oral health is crucial for targeted interventions.

Purpose of the Study:

• To estimate the average and subgroup-specific effects of SHS exposure on tooth loss in US adults.
• To utilize advanced causal inference methods for robust analysis of observational data.
• To identify specific populations disproportionately affected by SHS-related tooth loss.

Main Methods:

• Analysis of cross-sectional data from 6,019 non-smoking US adults (National Health and Nutrition Examination Survey, 2009-2018).
• Serum cotinine levels used to define SHS exposure.
• Targeted minimum loss estimation (doubly robust estimator) for association quantification.
• Causal forest method to evaluate heterogeneity and identify subgroup effects.

Main Results:

• SHS exposure was associated with an average of 0.74 fewer teeth.
• SHS exposure increased the probability of having fewer than 20 teeth by 4.6 percentage points.
• Greater tooth loss associations were observed in adults aged ≥45, those with lower socioeconomic position, higher sugar intake, comorbidities, or extreme flossing frequencies.

Conclusions:

• SHS exposure is significantly associated with increased tooth loss in US adults.
• Disproportionate oral health burdens from SHS are evident in vulnerable populations, including those with socioeconomic disadvantages and chronic health conditions.
• Integrating oral health into tobacco control and tailoring prevention strategies for high-risk groups are recommended.